Method of making gold leaf and product thereof



' F. DEMEL `uneZl, 1938.

METHOD OF MAKNG GOLD LEAF AND PRODUCT THEREOF Filed June l5, 1956 a9 o. mw Q Q v INVENTOR Fr'edrch em RNEY HIS

vPatented June 21, v1938 vv `vl4.Milliin-:n STATES VPari-:NT oF-Fics METHOD or MAKING Goan LEAF. Anp.' raonnc'r Tnsaaor Frederick Demel, Grantwood, N, J. Appiicauon June 15, 193s, sie-nai No. 85,351

9V Claims.

The invention relates to the production of improved gold leaf of any desired facial dimension and thickness and the product thereof.

Generally, this invention relates tothe production of gold, its alloys and other metals, usually .a so-termed precious metal, of any desired diengagement with a plate of base metal, until the plate of gold is reduced in thickness to the desired dimension, andthen suitably Vremoving the base metal and deriving the gold in desired status.

Pursuant to preferred forms of my process, gold or equivalent metal as a. composite with other metals, usually a relatively base metal, say, a three-layer composite, i. e., one layer of base metal on the opposing sides of such gold layer,

is subjected to continuous rolling treatment,

whereby the thickness of such gold layer is reduced tothe desired dimension, thereafter re,- moving the layer of base metal fully from one face of such rolled composite, while removing theV layer of base -metalfrom the opposite face but partially, then employing such partially removed metal as a support in a subsequent continuous treatment effecting the freeing of the gold, and then positioning the free gold continuous upon a strip of paper 'or equivalent, orv otherwise as l desired.

'Illustrating the instance of `gold and gold alloys,

pursuant to my preferred procedure, the initial.

.composite may-be formed of a` plate of gold of .desirably having a uniform thickness throughout metal, such as dilute nitric-'acid for copper as a thickness which is readily handled, the plate its length, applying'a layer of base metal, say copper, having a thickness appreciably greater than that of the gold plate, to one face of the gold plate, and applying to the opposite face of the gold plate ,a separate layer of copper or other base metal, the effective thickness of one layer of base metal being less than the effective thickness of vbase metal on the. opposite face; Such three-layer composite is then subjected to successive stages of rolling, thereby substantially proportionately reducing the respective thick--V nesses' of the three layers, the rolling or equivalent operation being carried out until the thickness of the intermediate gold layer is reduced to the desired dimension. Thereupon, the rolled composite 'is subjected on both faces to a bath of a medium unaflecting the gold layer`but capableA of removing, usually dissolving, the base the base metal, the duration of such treatment being carried out to wholly remove the base metal from one face of the gold, say, the `layer of base' metal of lesser thickness. 'The resulting two-layer composite is then subjected toa subsequent bath of removing medium unaiecting the gold layer but capable of removing the base metallayer, say a solution of nitric acid for copper, vthe base metal layer being disposed below the gold layer, thus freeing the gold. The freedomvv -gold is suitably treated as desired. Usually.' the freed vgold is positioned upon .a length of paper' 4 for mechanical support and to facilitate its use in the arts.'

Gold derived by my process by virtue of the rolling treatment, is characterized by a physical structure of'high density, uniformity of thickness, uniformity of reflected and translucentcolor and luster, and other superior physical characteristics, notably full clevoidance of tendency to curl. In contrast with thegold leaf made pursuant to my process, beaten gold, by reason of its manner of manufacture, is inherently devoid of uniformity of thickness, i: e. thinness, being thicker at and toward its edge portions, and `in consequence does not possess uniformity ofcolor by reected light nor uniformity of color by translucent light. Also, in contrast with my gold leaf pursuant to my process asset forth herein. electrolytic gold by reason of the presence of release of hydrogen gas at the cathode upon which the gold is deposited, has the tendency to curl, particularly at its edges, which curling tendency persists upon subdividing the electrolytic gold leaf. Also, electrolytic gold by reason of its production by electrodeposition, is constituted of no'n-densied crystals and other physical constitution giving rise, particularly when alloyed with base metals such as silver and/or copper,` to non-uniformity of color by reected light and non-uniformity of color by translucent light. i

By my process the resultant gold is obtained oi indefinite length, whereas beaten gold is limited in superficial dimension by the inherent restrictions imposed by the beating operation.

It desired, gold produced by my process may have a thinness comparable to that of beaten gold, that Vis to say,'of the order .of four millionth of an inch. I The base metal on one face of the gold plate of such composite, which is subjected to rolling treatment, may be diil'erent from the base metalon the opposite face o!v the gold plate, and the thickness of the respective layers of`- base metals may be equal or unequal, the objective being that upon subjecting the rolled composite to a suitable removing medium, the base metal layer or layers are removed, and the freed gold disposed to enable the same to be suitably supported and utilized as desired.

Further features and objects of the invention will be more fully understood from the following detail description and the accompanying drawing, in which Fig. lis a side elevation, largely diagrammatic indicating an initial treatment of rolling of a three-layer composite, the intermediate layer being, say, of gold or its alloy, and the twolayers respectivelyon opposite sides of the gold layer being of base metal.

Fig. 2 is a side elevation, similar to Fig. 1, also in diagrammatic form, illustrating a subsequent stage of rolling treatment.

Fig. 3 is an elevation in vertical section, in dlagrammatic form, illustrating a continuous treatment, pursuant to my invention, viz., the subjection of such rolled three-layer composite strip `to successive baths, firstly, for the removal of base metal wholly from one face of the gold layer and the partial removal of base metal from the opposite face of the 'gold layer, by means of a medium unaflrecting the gold layer but capable of removing, usually dissolving, the base metal, thence to av subsequentvbath for the whole removal of such partially removed layer of base metal, thence through suitable washing and/or other treating baths for the removal of all foreign material, and ultimately positioning the freed gold upon one face of a roll of indefinite length of a paper strip.

Fig. fi is a detail vertical section on line 4-4 of Fig. 3.

Fig. 5 is a perspective view of gold or equivalent freely lying on a strip of paper, of indefinite length, and wound as a roll.

Throughout the specification and claims,.for simplicity, I employ the term leaf to designate variant dimensions of thickness or thinness applicable to a plate, foil, film, etc., inclusive ofleaf also, I employ thel term gold to designate pure gold, gold alloys and other metals, usually a precious metal, the leaf of which is desired to be produced; also,'by the term copper I designate a metal other than gold, usually a base metal, employed on either or both faces of the intermediate gold layer, utilized in carrying out my process. I

Referring to the drawing which illustrates preferred individual steps and preferred sequence of individual steps for carrying out my process: In Fig. 1, I illustrate a three-layer composite `strip comprising an intermediate layer III of gold, on one face of which is applied a layer II of copper; a layer I2 of copper is applied to the opposite face of the gold layer. The thickness of. one layer, say, the layer I2, is illustrated less than the thickness of the opposite layer, i. e.

the' layer I I.

At I3, I4, are indicated a pair of rolls of a conventional or other approved rolling mill, the num-4 ber of additional sets of rolls I3, Il, being as desired.

As is indicated in Fig. 1. the normal operation of such chain of rolls I3, I4, functions primarily to reduce the over-all thickness of the composite metal layers, -without substantial increase in width of the composite metal layers.

In Fig'.'2, `illustrating a subsequent stage of the rolling, operation indicated in Fig. 1, the overall thicknesses of the rolled composite three layers Fundamentally, by such rolling or equivalent operation, the thickness of the intermediate gold layer III is graduately reduced to uniform thickness by the successive rolling treatments. until the desired thickness or thinness of the gold layer I0 is that of the leaf to be obtained. By such rolling or equivalent operation, the opposing layers II, I2, are substantially proportionately reduced in individual thickness dimensions.

Desirably, the rolling or equivalent operation is carried out to obtain a composite suiliciently pliable to afford winding into a coll.

The `resulting length of composite metal layer is then suitably treated for the full removal of the copper layer I2 and the partial removal of the copper layer II.

If desired, as indicated in Fig. 3, the thus coiled `multiple layer composite, as is indicated at I5,

may be continuously fed as an indefinite length into a bath I6, of suitable medium for removing copper, say, a bath of dilutenitric acid for the removal of copper, such bath being contained in a suitable tank I'I. At I8, I9, I indicate suitable supply and withdrawal piping, preferably for maintaining a desired strength of solution. By such removing treatment the layer I2 of copper" is wholly removed and the layer I I of copper is but partially removed. Most preferably, the piping I8, I9, forms a part of. a circuit connecting with a suitable supply of nitric acid or equivalentcopper" removing medium, and also with suitable means serving for the recovery of copper, if desired.

Advantageously, the procedure of removal-of i the opposing copper layers is carried out in a continuous manner, as is indicated in Fig. 3, the bath 20 representing a bath, say of dilute nitric acid, for the completion of the removal of the theretofore partially removed layer II of copper. I5a indicates such 4two-layer composite, the gold" layer I0 lying above the partially removed, under layer I I of copper, resulting from l the treatment in the previous removal bath I6.l

The bath 2i represents a bath such as of water,

and the bath 22 represents a bath such as al-A `layer, is preferably passed in transit upon the surface of the bath 20, the thus freed gold leaf, indicated at Illa in Fig. 3, being suitably mechanically. supported and conveyed through they respective baths 20, 2|, 22, etc. for final disposition.v

Fig. 3 illustrates also a method of iinaldisposition of the gold leafl Illa by laying the gold in free status upon a strip of suitable material v such as of paper, supplied, say, 'from a roll 23 and conveyed in suitable adjacent relationship rela--l tive to the freed gold leaf IIIa, as by the -intermediation of a roller 24 about which the paper strip 23a is passed tov elevate the freed gold Ia from the bath 22andf'freely lay the 'gold upon the paper strip.

' Fig. 5 illustrates suchfleaffof gold I Ila, of

I great length and of ,uniform thickness throughout its length,freely positioned upon an indefinite ucts, as iswell known toitlhose skilled `in the art. 'I'he tank 2l is preferably provided with supply length of paper strip 23a resulting from the above or equivalent treatment. Roll gold, i. e. gold leaf wound (spirally) on paper and/or other inert carrier,l nds wide application in the industrial art of stamping requiring continuous, i. e. repeated operations, as in stamping book covers, tipping of sweat bands and inside linings of hats, brand and trade-name marking of various prodand withdrawal piping, indicated at 26, 21. The tank 22, whichmay .contain an alcohol bath; is

`provided with supply and withdrawal piping'ZG, 21', connected preferaby in circuit with a source of alcohol, and more preferably arranged for recovery of alcohol content. v

At 28, 28a, are indicated mechanical transferring means for elevating and transferring the released indefinite length of gold film ma frombath to bath, as from bath 20 to the succeeding bath 2i, and correspondingly from the bath 2l tothe succeeding bath 22. Such transferring ,means advantageously comprises, as shown, an

ably including a set of feed rolls 3 i 3 l for positivel ly feeding the composite strip ita. to theerst bath,

say,'the bath 2'@ of the copper" removing medium, a desirable arrangement being indicated in Fig. 3. The positive drive from the shaft 3G to the respective film transferring meansv, 23a,'

etc., and includingy the paper-gold lm positioning roll 2t, are indicated in the form of screws secured .to the shaft 3i! and meshing with suitable screw gears 32, respectively secured to the shafts of the stated actuated devices, such as indicated with respect to .the rollers 33 driving the respective belts 29 of the transfer devices 28, 28d, etc.

In illustration of the employment of different base metals for the layers I l, I2, zinc may be employed on one face-and copper onl the other face. the thickness of such opposing layers of zinc and copper being coordinated -with respect to the rates of solution of zincand copper, in the removing medium, so as to provide for the whole removal of one base metal from one face of the rolled gold layer, the layer on the opposing face being either but partially removed, or'otherwise of suitably reduced thickness, to serve as a support in the subsequent treatment for the release of the gold lm. 1

A Whereas, I. have set/forth my invention in re spect to specic details of the more preferred procedure, it -is understood that many changes and modiiic'ations 4may be made without departing from thespirit of the invention.

In the below appearing claims, the terms gold.', copper and leaf" are employed as above defined. Further, 1 employ the term great length to define a length materially exceeding the length of beaten gold,usually not greater vthan seven inches. Y

@I claim: y

1. The methgd of continuously producingi` gold in leaf form, which comprises subjecting a strip of gold of an indefinite length continuously iritermediate opposing strips of copper of indefinite lengths to continuous thicknessreducing operation under prssure,.to attain the desired ,thickvness of the leaf, then whollyl removing the copper from one face of the gold, and removing the copper fromthe opposing faceof the gold while recovering the gold in leaf form.

2. The method of continuously producing gold in leaf form,'which comprises subjecting to continuous pressure treatment a composite layer of individual layers of gold land copper of indefinite lengths, the .layer of gold beingdisposed intermediate layers of copper, one layer of copper being `of less eiiective thickness than the opposing copper layerythen wholly removing the coplper from one face 'of the gold layer, and removing the copper from the opposing face of the gold layer while recovering thev gold in leaf form.

3. The method of continuously producing gold leaf Iwhich comprises subjecting to .continuous mechanical rolling a composite layerfof individual layers of gold and copper of indefinite lengths,

- the layer of gold being disposed intermediate layers of copper, the thickness of one copper layer 'being less thanv that of the other copper layer,

then removing\wholly the copper from one face of the gold layer by immersion in a bath of suitable solvent, and continuously removing the copper from. the opposing faceI of the gold layer while continuously recovering the gold in leaf form.

' 4. The method of continuously producing goldv leaf which comprises subjecting to continuous A'mechanical rolling, a composite layer of individual layers of gold and copper of indefinite lengths, -the layer of gold being disposed intermediate layers of copper, one layer of vcopper being' of less effective thickness than the other copper layer,

thenv continuously Wholly removing the copper metal from one facev of the gold layer by immersion in aA bath of suitable solvent while partially removing `the opposite copper layer, then continuously removing the theretofore partially removed copper -from such opposite face of the gold layer byimmersion in a bath of suitable solvent, and continuously recovering the gold in leaf form.

5. The method of continuously producing gold leaf which comprises subjecting to continuous mechanical. rolling, a composite layer of individual layers of gold and copper of indefinite lengths, 'the layer of gold being disposed inter mediate layers of copper, one layer ofcopper being of less effective thickness than the ,other copper layer," then continuously. wholly removing the copper layer from one face of the gold layer by immersion in a bath of suitable solvent while- -partially removing the opposite copper layer,.

then continuouslyiremoving the theretofore partially removed copper from such opposite face of the gold layer by immersion in a bath of suitable solvent, the goldl layer being disposed above vthe copper layer while passing through the second mentioned bath, and continuously recovering the gold in leaf form. y

6. 'I'he method of,continuously producing gold leaf which comprises subjecting to continuous mechanical rolling, a composite layer 'of individual layers of gold and copper of indefinite lengths, `the layer of gold being disposed intermediate 'layers of copper, one layer of copper being of less effective thickness than the other copper layer, then continuously wholly removing thecopper layer from o ne face of the gold layer by immersion in a bath of suitable solvent while partially removing the opposite copper layer,`then continuously removing the theretofore partially removed copper from such opposite face of the gold layer by immersion in a bath of suitable solvent, the gold layer being disposed at the surface level of the second mentioned bath above lytically deposited gold, and` characterized by having been worked and possessing uniformity of reflected color` and uniformity of ,`translucent o color.

8. Gold leaf of a great length and having a Y the gold in leaf form.

uniform thickness throughout. its length, the thickness of the same being of the order of magnitude of four millionths of an inch, possessing density materially greater than that of electrolytically deposited gold, characterized by having been worked and possessing uniformity of color 'by reected light, uniformity of color by translucent light, and devoid of the tendency to curl.l 9. The method of continuously producing gold in leaf form, which comprises subjecting to continuous pressure treatment a composite layer comprising a layer of gold disposed intermediate layers of materials having mutually different rates of solubility, all of said layers being in continuous strip form of great length, then removing wholly the material from one face of the gold layer by immersion in a bath of suitable solvent, then removing` the material from the opposing face of the goldlayer while recovering- FREDERICK DEMEL. 

